Support device for a stent and a method of using the same to coat a stent

ABSTRACT

A support device for a stent and a method of coating a stent using the device are provided.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a support device for a stent and a method ofcoating a stent using the device.

2. Description of the Background

Blood vessel occlusions are commonly treated by mechanically enhancingblood flow in the affected vessels, such as by employing a stent. Stentsact as scaffoldings, functioning to physically hold open and, ifdesired, to expand the wall of the passageway. Typically, stents arecapable of being compressed, so that they can be inserted through smalllumens via catheters, and then expanded to a larger diameter once theyare at the desired location. Examples in the patent literaturedisclosing stents include U.S. Pat. No. 4,733,665 issued to Palmaz, U.S.Pat. No. 4,800,882 issued to Gianturco, and U.S. Pat. No. 4,886,062issued to Wiktor.

FIG. 1 illustrates a conventional stent 10 formed from a plurality ofstruts 12. The plurality of struts 12 are radially expandable andinterconnected by connecting elements 14 that are disposed betweenadjacent struts 12, leaving lateral openings or gaps 16 between adjacentstruts 12. Struts 12 and connecting elements 14 define a tubular stentbody having an outer, tissue-contacting surface and an inner surface.

Stents are used not only for mechanical intervention but also asvehicles for providing biological therapy. Biological therapy can beachieved by medicating the stents. Medicated stents provide for thelocal administration of a therapeutic substance at the diseased site.Local delivery of a therapeutic substance is a preferred method oftreatment because the substance is concentrated at a specific site andthus smaller total levels of medication can be administered incomparison to systemic dosages that often produce adverse or even toxicside effects for the patient.

One method of medicating a stent involves the use of a polymeric carriercoated onto the surface of the stent. A composition including a solvent,a polymer dissolved in the solvent, and a therapeutic substancedispersed in the blend is applied to the stent by immersing the stent inthe composition or by spraying the composition onto the stent. Thesolvent is allowed to evaporate, leaving on the stent surfaces a coatingof the polymer and the therapeutic substance impregnated in the polymer.

A shortcoming of the above-described method of medicating a stent is thepotential for coating defects. While some coating defects can beminimized by adjusting the coating parameters, other defects occur dueto the nature of the interface between the stent and the apparatus onwhich the stent is supported during the coating process. A high degreeof surface contact between the stent and the supporting apparatus canprovide regions in which the liquid composition can flow, wick, andcollect as the composition is applied. As the solvent evaporates, theexcess composition hardens to form excess coating at and around thecontact points between the stent and the supporting apparatus. Upon theremoval of the coated stent from the supporting apparatus, the excesscoating may stick to the apparatus, thereby removing some of the coatingfrom the stent and leaving bare areas. Alternatively, the excess coatingmay stick to the stent, thereby leaving excess coating as clumps orpools on the struts or webbing between the struts.

Thus, it is desirable to minimize the interface between the stent andthe apparatus supporting the stent during the coating process tominimize coating defects. Accordingly, the present invention providesfor a device for supporting a stent during the coating applicationprocess. The invention also provides for a method of coating the stentsupported by the device.

SUMMARY OF THE INVENTION

In accordance with one aspect of the invention a support device for astent is provided. In one embodiment, the support device includes a bodyhaving a first end and a second end and at least three sides extendingfrom the first end to the second end, wherein the three sides arecapable of penetrating at least partly into one end of a stent. Any ofthe sides can have a variety of geometrical configurations such ashaving a radius of curvature or being V-shaped.

In accordance with another embodiment of the invention, an apparatus forsupporting a stent during a process of applying a coating material tothe stent is provided. The apparatus includes a first member having anend configured to penetrate at least partially in one end of a stent;and a second member having an end configured to penetrate at leasepartially in the opposing end of the stent. Each of the ends cancomprise two non-parallel sides for allowing the stent to rest on theends during the process of applying the coating material. A third membercan be included and adapted to extend through the stent for connectingthe first member to the second member.

In accordance with another embodiment of the invention a device forsupporting a stent includes a structure of a variable size so as toallow a section of the structure to penetrate into a first end of thestent until the size of the structure prevents the structure frompenetrating deeper into the first end of the stent. The section of thestructure that is capable of penetrating into the first end of the stentincludes a surface that is in contact with the stent such that thesurface that is in contact with the stent does not extend around theentire perimeter of the section.

A second structure of a variable size can also be provide so as to allowa section of the second structure to penetrate into a second, opposingend of the stent until the size of the structure prevents the structurefrom penetrating deeper into the second end of the stent. The section ofthe second structure that is capable of penetrating into the second endof the stent includes a surface that is in contact with of the stentsuch that the surface that is in contact with the stent does not extendaround the entire perimeter of the section of the second structure.

In one variation, the second structure is capable of being moved towardsor away from the structure for releasably pinching the stent between thestructure and the second structure.

In accordance with another aspect of the invention, a method can also beprovided for depositing a coating substance on the stent supported byany one the various described embodiments of the present invention. Thecoating material can be applied by a spray process or by immersing thestent in the coating material. The coating material can comprise apolymer mixed a fluid and optionally a therapeutic substance addedthereto.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 illustrates a conventional stent.

FIG. 2 illustrates a mounting assembly for supporting a stent.

FIG. 3 illustrates an expanded perspective view of the mountingassembly, in accordance with one embodiment of the present invention.

FIG. 4 illustrates the interface between the mounting assembly and thestent in accordance with one embodiment of the present invention.

FIGS. 5A-5D illustrate the perspective, side, top and front views of asupport element for the mounting assembly in accordance with oneembodiment of the present invention.

FIGS. 6A and 6B illustrate the perspective and front views of thesupport element in accordance with another embodiment of the presentinvention.

FIGS. 7A and 7B illustrate the perspective and front views of thesupport element in accordance with another embodiment of the presentinvention.

FIGS. 8A, 8B, and 8C illustrate the perspective, side and front views ofthe support element in accordance with another embodiment of the presentinvention.

DETAILED DESCRIPTION Embodiments of the Mounting Assembly

Referring to FIG. 2, a mounting assembly 2 for supporting stent 10 isillustrated to include a first member 22, a mandrel 24, and a secondmember 26. First member 22 can connect to a motor 28A so as to providerotational motion about the longitudinal axis of stent 10, as depictedby arrow 30, during the coating process. Another motor 28B can also beprovided for moving~ mounting assembly 20 in a linear direction, backand forth, along a rail 32. The type of stent is not of criticalsignificance and the term stent is broadly intended to includestent-grafts or radially expandable stents, such as balloon-expandablestents or self-expandable stents.

Referring to FIG. 3, a first support element 34 can be a part of ordisengagably coupled to first member 22. First support element 34 isconfigured to penetrate at least partially into one end of stent 10, asillustrated in FIG. 4. In accordance with one embodiment, mandrel 24 canbe permanently affixed to first support element 34. Alternatively, firstmember 22 and first support element 34 can include a bore 36 forreceiving a first end 38 of mandrel 24. First end 38 of mandrel 24 canbe threaded to screw into bore 36. Alternatively, a non-threaded firstend 38 of mandrel 24 can be press-fitted or friction-fitted within bore36. Bore 36 should be deep enough so as to allow mandrel 24 to securelymate with first member 22. The depth of bore 36 can also beover-extended so as to allow a significant length of mandrel 24 topenetrate bore 36. This would allow the length of mandrel 24 to beadjusted to accommodate stents of various sizes.

The outer diameter of mandrel 24 should be smaller than the innerdiameter of stent 10 so as to prevent the outer surface of mandrel 24from making contact with the inner surface of stent 10. A sufficientclearance between the outer surface of mandrel 24 and the inner surfaceof stent 10 should be provided to prevent mandrel 24 from obstructingthe pattern of the stent body during the coating process. By way ofexample, the outer diameter of mandrel 24 can be from about 0.010 inches(0.254 mm) to about 0.017 inches (0.432 mm) when stent 10 has an innerdiameter of between about 0.025 inches (0.635 mm) and about 0.035 inches(0.889 mm).

Second member 26 can include an second support element 40 forpenetrating into the opposing end of stent 10 (see FIG. 4). A second end42 of mandrel 24 can be permanently affixed to second member 26 if end38 is disengagable from support member 22. Alternatively, in accordancewith another embodiment, mandrel 24 can have a threaded second end 42for screwing into a bore 44 of second member 26. Bore 44 can be of anysuitable depth that would allow second member 26 to be incrementallymoved closer to first member 22. Accordingly, stents 10 of any lengthcan be securely pinched between first and second members 22 and 26. Inaccordance with yet another embodiment, a non-threaded second end 42 andbore 44 combination can be employed such that second end 42 ispress-fitted or friction-fitted within bore 44 to prevent movement ofstent 10 on mounting assembly 20.

As illustrated in FIG. 4, mounting assembly 20 supports stent 10 viasupport elements 34 and 40. Opposing forces exerted from supportelements 34 and 40, for securely pinching stent 10, should besufficiently strong so as to prevent any significant movement of stent10 on mounting assembly 20. However, the exerted force should notcompress stent 10 so as to distort the body of stent 10. Over or underapplication of support force can lead to problems such as stent 10resting too loosely on mounting assembly 20, stent 10 bending and thuscontacting mandrel 24, opposing ends of stent 10 flaring on supportelements 34 and 40, and increased contact between stent 10 and supportelements 34 and 40, all of which can lead to coating defects.

In addition to supporting stent 10 so as to prevent any significantmovement of stent 10 on mounting assembly 20 during the coating process,support elements 34 and 40 should provide minimal contact between stent10 and mounting assembly 20, thereby minimizing the potential forcoating defects due to the stent 10-mounting assembly 20 interface.

For ease of discussion, reference will hereinafter be made to firstsupport element 34. However, it is understood that first support element34 can be identical or substantially similar to second support element40, and thus, the following discussion of first support element 34applies equally to second support element 40. In accordance to oneembodiment, as illustrated in FIGS. 5A-5D, support element 34 includes afront end 46 and a back end 48 and four sides 50A-50D. In oneembodiment, one of the pairs of the opposing sides, such as sides 50Band 50D, can be non-parallel. In other words, the width w_(f) of frontend 46 is equal to the width w_(b) of the back end, while the heighth_(f) of front end 46 is less than the height h_(b) of back end 48.Accordingly, sides 50B and 50D taper at an angle φ, which can be fromabout 15° to about 75°, for example about 45°. Width W_(f) and heighth_(f) of front end 46 should be smaller than the inner diameter d of thestent employed while height h_(b) of back end 48 should be larger thanthe inner diameter d of the stent (the inner diameter refers to thediameter of the stent, whether expanded or unexpanded, as positioned onmounting assembly 20). Accordingly, support element 34 is capable ofonly partially penetrating into the end of a stent—until the size of thestructure prevents support element 34 from penetrating deeper into thestent. FIG. 5D illustrates stent 10 resting on sides 50B and 50D, whilesides 50A and 50C do not make contact with stent 10.

In an alternative variation of FIGS. 5A-5D, in FIGS. 6A and 6B, widthw_(f) can be smaller than width w_(b) such that each pair of opposingside 50A-50D is non-parallel. As illustrate in FIG. 6B, support element34 can partially penetrate into the end of stent 10 allowing stent 10 tomake contact with and rest on edges 52A-D. Thus minimum contact is madebetween stent 10 and support element 34.

In yet another variation, as illustrated in FIGS. 7A and 7B, sides 50Band 50D can be curved or have a radius of curvature. The radius ofcurvature of sides 50B and 50D can be the same as the radius ofcurvature of the inner circumference of the stent so as to allow stent10 to fittingly rest on sides 50B and 50D.

A variety of shapes can be contemplated by one of ordinary skill in theart for support elements 34 and 40. For example, a geometricalconfigurations such as that illustrated in FIGS. 8A-8C can be employedso as to provide adequate support for a stent without being in too muchcontact with the stent so as to cause coating defects. FIGS. 8A-8Cillustrate nonparallel sides 50B and 50D being V-shaped. Height h_(f) offront end 46 is less than the height h_(b) of back end 48 so as toprovide a taper at an angle φ, for the V-shaped sides 50B and 50D. Stent10 will be resting on edges 54 of sides 50B and 50D upon insertion ofsupport element 34 into the end of the stent.

Coating a Stent Using the Mounting Assembly

The following method of application is being provided by way ofillustration and is not intended to limit the embodiments of mountingassembly 20 of the present invention. A spray apparatus, such as EFD780S spray device with VALVEMATE 7040 control system (manufactured byEFD Inc., East Providence, R.I. , can be used to apply a composition toa stent. EFD 780S spray device is an air-assisted external mixingatomizer. The composition is atomized into small droplets by air anduniformly applied to the stent surfaces. The atomization pressure can bemaintained at a range of about 5 psi to about 20 psi. The droplet sizedepends on such factors as viscosity of the solution, surface tension ofthe solvent, and atomization pressure. Other types of spray applicators,including air-assisted internal mixing atomizers and ultrasonicapplicators, can also be used for the application of the composition.

During the application of the composition, a stent supported by mountingassembly 20 can be rotated about the stent's central longitudinal axis.Rotation of the stent can be from about 1 rpm to about 300 rpm, morenarrowly from about 50 rpm to about 150 rpm. By way of example, thestent can rotate at about 120 rpm. The stent can also be moved in alinear direction along the same axis. The stent can be moved at about 1mm/second to about 12 mm/second, for example about 6 mm/second, or for aminimum of at least two passes (i.e., back and forth past the spraynozzle). The flow rate of the solution from the spray nozzle can be fromabout 0.01 mg/second to about 1.0 mg/second, more narrowly about 0.1mg/second. Multiple repetitions for applying the composition can beperformed, wherein each repetition can be, for example, about 1 secondto about 10 seconds in duration. The amount of coating applied by eachrepetition can be about 0.1 micrograms/cm² (of stent surface) to about10 micrograms/cm², for example less than about 2 micrograms/cm² per5-second spray.

Each repetition can be followed by removal of a significant amount ofthe solvent(s). Depending on the volatility of the particular solventemployed, the solvent can evaporate essentially upon contact with thestent. Alternatively, removal of the solvent can be induced by bakingthe stent in an oven at a mild temperature (e.g., 60° C.) for a suitableduration of time (e.g., 2-4 hours) or by the application of warm air.The application of warm air between each repetition prevents coatingdefects and minimizes interaction between the active agent and thesolvent. The temperature of the warm air can be from about 30° C. toabout 60° C., more narrowly from about 40° C. to about 50° C. The flowrate of the warm air can be from about 20 cubic feet/minute (CFM) (0.57cubic meters/minute (CMM)) to about 80 CFM (2.27 CMM), more narrowlyabout 30 CFM (0.85 CMM) to about 40 CFM (1.13 CMM). The warm air can beapplied for about 3 seconds to about 60 seconds, more narrowly for about10 seconds to about 20 seconds. By way of example, warm air applicationscan be performed at a temperature of about 50° C., at a flow rate ofabout 40 CFM, and for about 10 seconds. Any suitable number ofrepetitions of applying the composition followed by removing thesolvent(s) can be performed to form a coating of a desired thickness orweight. Excessive application of the polymer in a single applicationcan, however, cause coating defects.

In an alternative method of applying the composition, a stent supportedby mounting assembly 20 can be immersed in the composition. The solventcan then be allowed to evaporate from the composition to form a coatingon the stent.

Operations such as wiping, centrifugation, or other web clearing actscan also be performed to achieve a more uniform coating. Briefly, wipingrefers to the physical removal of excess coating from the surface of thestent; and centrifugation refers to rapid rotation of the stent about anaxis of rotation. The excess coating can also be vacuumed off of thesurface of the stent.

In accordance with one embodiment, the stent can be at least partiallypreexpanded prior to the application of the composition. For example,the stent can be radially expanded about 20% to about 60%, more narrowlyabout 27% to about 55%—the measurement being taken from the stent'sinner diameter at an expanded position as compared to the inner diameterat the unexpanded position. The expansion of the stent, for increasingthe interspace between the stent struts during the application of thecomposition, can further prevent “cob web” formation between the stentstruts.

In accordance with one embodiment, the composition can include a solventand a polymer dissolved in the solvent and optionally a wetting fluid.The composition can also include active agents, radiopaque elements, orradioactive isotopes. Representative examples of polymers that can beused to coat a stent include ethylene vinyl alcohol copolymer (commonlyknown by the generic name EVOH or by the trade name EVAL),poly(hydroxyvalerate); poly(L-lactic acid); polycaprolactone;poly(lactide-co-glycolide); poly(hydroxybutyrate);poly(hydroxybutyrate-co-valerate); polydioxanone; polyorthoester;polyanhydride; poly(glycolic acid); poly(D,L-lactic acid); poly(glycolicacid-co-trimethylene carbonate); polyphosphoester; polyphosphoesterurethane; poly(amino acids); cyanoacrylates; poly(trimethylenecarbonate); poly(iminocarbonate); copoly(ether esters) (e.g. PEO/PLA);polyalkylene oxalates; polyphosphazenes; biomolecules, such as fibrin,fibrinogen, cellulose, starch, collagen and hyaluronic acid;polyurethanes; silicones; polyesters; polyolefins; polyisobutylene andethylene-alphaolefin copolymers; acrylic polymers and copolymers; vinylhalide polymers and copolymers, such as polyvinyl chloride; polyvinylethers, such as polyvinyl methyl ether; polyvinylidene halides, such aspolyvinylidene fluoride and polyvinylidene chloride; polyacrylonitrile;polyvinyl ketones; polyvinyl aromatics, such as polystyrene; polyvinylesters, such as polyvinyl acetate; copolymers of vinyl monomers witheach other and olefins, such as ethylene-methyl methacrylate copolymers,acrylonitrilestyrene copolymers, ABS resins, and ethylene-vinyl acetatecopolymers; polyamides, such as Nylon 66 and polycaprolactam; alkydresins; polycarbonates; polyoxymethylenes; polyimides; polyethers; epoxyresins; polyurethanes; rayon; rayon-triacetate; cellulose; celluloseacetate; cellulose butyrate; cellulose acetate butyrate; cellophane;cellulose nitrate; cellulose propionate; cellulose ethers; andcarboxymethyl cellulose.

“Solvent” is defined as a liquid substance or composition that iscompatible with the polymer and is capable of dissolving the polymer atthe concentration desired in the composition. Examples of solventsinclude, but are not limited to, dimethylsulfoxide (DMSO), chloroform,acetone, water (buffered saline), xylene, methanol, ethanol, 1-propanol,tetrahydrofuran, 1-butanone, dimethylformamide, dimethylacetamide,cyclohexanone, ethyl acetate, methylethylketone, propylene glycolmonomethylether, isopropanol, isopropanol admixed with water, N-methylpyrrolidinone, toluene, and combinations thereof.

A “wetting” of a fluid is measured by the fluid's capillary permeation.Capillary permeation is the movement of a fluid on a solid substratedriven by interfacial energetics. Capillary permeation is quantitated bya contact angle, defined as an angle at the tangent of a droplet in afluid phase that has taken an equilibrium shape on a solid surface. Alow contact angle means a higher wetting liquid. A suitably highcapillary permeation corresponds to a contact angle less than about 90°.Representative examples of the wetting fluid include, but are notlimited to, tetrahydrofuran (THF), dimethylformamide (DMF), 1-butanol,n-butyl acetate, dimethylacetamide (DMAC), and mixtures and combinationsthereof.

The active agent can be for inhibiting the activity of vascular smoothmuscle cells. More specifically, the active agent can be aimed atinhibiting abnormal or inappropriate migration and/or proliferation ofsmooth muscle cells for the inhibition of restenosis. The active agentcan also include any substance capable of exerting a therapeutic orprophylactic effect in the practice of the present invention. Forexample, the agent can be for enhancing wound healing in a vascular siteor improving the structural and elastic properties of the vascular site.Examples of agents include antiproliferative substances such asactinomycin D, or derivatives and analogs thereof (manufactured bySigma-Aldrich 1001 West Saint Paul Avenue, Milwaukee, Wis. 53233; orCOSMEGEN available from Merck). Synonyms of actinomycin D includedactinomycin, actinomycin IV, actinomycin I₁, actinomycin X₁, andactinomycin C₁. The active agent can also fall under the genus ofantineoplastic, antiinflammatory, antiplatelet, anticoagulant,antifibrin, antithrombin, antimitotic, antibiotic, antiallergic andantioxidant substances. Examples of such antineoplastics and/orantimitotics include paclitaxel (e.g. TAXOL® by Bristol-Myers SquibbCo., Stamford, Conn.), docetaxel (e.g. Taxotere®, from Aventis S.A.,Frankfurt, Germany) methotrexate, azathioprine, vincristine,vinblastine, fluorouracil, doxorubicin hydrochloride (e.g. Adriamycin®from Pharmacia & Upjohn, Peapack N.J.), and mitomycin (e.g. Mutamycin®from Bristol-Myers Squibb Co., Stamford, Conn.). Examples of suchantiplatelets, anticoagulants, antifibrin, and antithrombins includesodium heparin, low molecular weight heparins, heparinoids, hirudin,argatroban, forskolin, vapiprost, prostacyclin and prostacyclinanalogues, dextran, D-phe-pro-arg-chloromethylketone (syntheticantithrombin), dipyridamole, glycoprotein IIb/IIIa platelet membranereceptor antagonist antibody, recombinant hirudin, and thrombininhibitors such as Angiomax™ (Biogen, Inc., Cambridge, Mass.). Examplesof such cytostatic or antiproliferative agents include angiopeptin,angiotensin converting enzyme inhibitors such as captopril (e.g.Capoten® and Capozide® from Bristol-Myers Squibb Co., Stamford, Conn.),cilazapril or lisinopril (e.g. Prinivil® and Prinzide® from Merck & Co.,Inc., Whitehouse Station, N.J.); calcium channel blockers (such asnifedipine), colchicine, fibroblast growth factor (FGF) antagonists,fish oil (omega 3-fatty acid), histamine antagonists, lovastatin (aninhibitor of HMG-CoA reductase, a cholesterol lowering drug, brand nameMevacor® from Merck & Co., Inc., Whitehouse Station, N.J.), monoclonalantibodies (such as those specific for Platelet-Derived Growth Factor(PDGF) receptors), nitroprusside, phosphodiesterase inhibitors,prostaglandin inhibitors, suramin, serotonin blockers, steroids,thioprotease inhibitors, triazolopyrimidine (a PDGF antagonist), andnitric oxide. An example of an antiallergic agent is permirolastpotassium. Other therapeutic substances or agents which may beappropriate include alpha-interferon, genetically engineered epithelialcells, rapamycin and dexamethasone.

Examples of radiopaque elements include, but are not limited to, gold,tantalum, and platinum. An example of a radioactive isotope is p³².Sufficient amounts of such substances may be dispersed in thecomposition such that the substances are not present in the compositionas agglomerates or flocs.

While particular embodiments of the present invention have been shownand described, it will be obvious to those skilled in the art thatchanges and modifications can be made without departing from thisinvention in its broader aspects. Therefore, the appended claims are toencompass within their scope all such changes and modifications as fallwithin the true spirit and scope of this invention.

What is claimed is:
 1. A support device for a stent, comprising: a bodyhaving a first end and a second end and at least three sides extendingfrom the first end to the second end, wherein the three sides arecapable of penetrating at least partially into one end of a stent forallowing the stent to rest thereon during application of coatingmaterial to the stent.
 2. The apparatus of claim 1, wherein two of thesides that are facing one another are non-parallel.
 3. The apparatus ofclaim 1, wherein the body comprises four sides, two of the sides whichare opposing one another are non-parallel and configured to allow thestent to rest thereon.
 4. The apparatus of claim 1, wherein at least oneof the sides has a radius of curvature.
 5. The apparatus of claim 1,wherein the body comprises four sides, two of the sides which areopposing one another are non-parallel, have a radius of curvature, andconfigured to allow the stent to rest thereon.
 6. The apparatus of claim1, wherein at least one of the sides is V-shaped.
 7. The apparatus ofclaim 1, wherein the body comprises four sides, two of the sides whichare opposing one another are non-parallel, V-shaped, and configured toallow the stent to rest thereon.
 8. An apparatus for supporting a stentduring a process of applying a coating material to the stent,comprising: a first member having an end configured to penetrate atleast partially in one end, of a stent; and a second member having anend configured to penetrate at least partially in a opposing end of thestent; wherein each of the ends comprises two non-parallel sides forallowing the stent to rest on the non-parallel sides during the processof applying the coating material.
 9. The apparatus of claim 8,additionally comprising a third member adapted to extend through thestent for connecting the first member to the second member.
 10. Theapparatus of claim 8, wherein at least one of the two non-parallel sidesis curved shaped.
 11. The apparatus of claim 8, wherein at least one ofthe two non-parallel sides is V-shaped.
 12. The apparatus of claim 8,wherein the non-parallel sides are facing one another.
 13. A device forsupporting a stent, the stent having an inner surface and an outertissue contacting surface, comprising: a structure of a variable size soas to allow a section of the structure to penetrate into a first end ofthe stent until the size of the structure prevents the structure frompenetrating deeper into the first end of the stent, wherein the sectionof the structure that is capable of penetrating into the first end ofthe stent includes a surface that is in contact with the stent such thatthe surface that is in contact with the stent does not extend around anentire perimeter of the section, the structure allowing the stent torest thereon during application of coating to the stent.
 14. The deviceof claim 13, additionally comprising a second structure of a variablesize so as to allow a section of the second structure to penetrate intoa second, opposing end of the stent until the size of the structureprevents the structure from penetrating further into the second end ofthe stent.
 15. The device of claim 14, wherein the second structure iscapable of being moved towards or away from the structure for releasablypinching the stent between the structure and the second structure. 16.The device of claim 14, wherein the section of the second structure thatis capable of penetrating into the second end of the stent includes asurface that is in contact with the stent such that the surface that isin contact with the stent does not extend around the entire perimeter ofthe section of the second structure.
 17. The device of claim 14,additionally including a third structure extending through the stent andconnecting the structure to the second structure, wherein the outersurface of the third structure does not contact the inner surface of thestent.